Retainer sleeve in a degradation assembly

Abstract

A degradation assembly has an attack tool with a body and a shank. The body has a wear resistant tip with a hardness of at least 60 HRc. The shank is disposed within a bore of a holder secured to a driving mechanism. A retainer sleeve is disposed around the shank of the attack tool, wherein an annular gap of 0.002 to 0.010 inches exists between at least a portion of the sleeve and the shank.

What is claimed is: 
     
       1. A degradation assembly comprising:
 an attack tool comprising a body and a shank, the body comprising a wear resistant tip comprising a hardness of at least 60 HRc; 
 the shank being disposed within a bore of a holder secured to a driving mechanism; and 
 a retainer sleeve disposed around the shank of the attack tool, the retainer sleeve comprising an inner surface with a carbide thickness of 0.0001 and 0.5 inches; and 
 a seal between the shank and the sleeve disposed proximate the rearward end of the shank; 
 wherein an annular gap of 0.002 to 0.007 inches exists between at least a portion of the sleeve and the shank. 
 
     
     
       2. The degradation assembly of  claim 1 , wherein the retainer sleeve comprises at least one protrusion extending from an inner surface of the sleeve. 
     
     
       3. The degradation assembly of  claim 2 , wherein the protrusion is a bump, a ring, a rib, or combinations thereof. 
     
     
       4. The degradation assembly of  claim 1 , wherein the inner surface of the sleeve is polished. 
     
     
       5. The degradation assembly of  claim 1 , wherein the inner surface comprises layers. 
     
     
       6. The degradation assembly of  claim 1 , wherein the inner surface is made of a polycrystalline ceramic with a binder concentration of 4 to 35 weight percent. 
     
     
       7. The degradation assembly of  claim 1 , wherein the retainer sleeve is a spring. 
     
     
       8. The degradation assembly of  claim 1 , wherein the retainer sleeve comprises a lip proximate an outer edge. 
     
     
       9. The degradation assembly of  claim 1 , wherein the retainer sleeve comprises a guide slot. 
     
     
       10. The degradation assembly of  claim 9 , wherein the shank comprises a guide pin, the guide slot of the retainer sleeve being adapted to receive the guide pin. 
     
     
       11. The degradation assembly of  claim 1 , wherein the retainer sleeve comprises a thickness from 0.01 to 0.5 inches. 
     
     
       12. The degradation assembly of  claim 1 , wherein a first end of the retainer sleeve comprises a larger diameter than a second end of the retainer sleeve. 
     
     
       13. The degradation assembly of  claim 1 , wherein the wear resistant tip comprises a material selected from the group consisting of chromium, tungsten, tantalum, niobium, titanium, molybdenum, carbide, natural diamond, polycrystalline diamond, vapor deposited diamond, cubic boron nitride, aluminum oxide, zircon, silicon, whisker reinforced ceramics, diamond impregnated carbide, diamond impregnated matrix, silicon bonded diamond, and combinations thereof. 
     
     
       14. The degradation assembly of  claim 1 , wherein the wear resistant tip comprises a binder concentration of 4 to 35 weight percent. 
     
     
       15. The degradation assembly of  claim 1 , wherein the wear resistant tip comprises an average grain size of 0.5 to 200 microns. 
     
     
       16. A method for manufacturing a degradation assembly comprising:
 providing an attack tool comprising a body and a shank, a holder comprising a bore, and a retainer sleeve; 
 adding a carbide material of a thickness of 0.0001 to 0.5 inches to an inner surface of the retainer sleeve; 
 adding a seal between the shank and the sleeve proximate a rearward end of the shank; 
 fitting the retainer sleeve around the shank of the attack tool, wherein an annular gap of 0.002 to 0.007 inches exists between at least a portion of the sleeve and the shank; and 
 inserting the shank and the retainer sleeve into the bore of the holder such that the retainer sleeve retains the shank within the bore.